AutoScaleTextView.java

/**

 * Mod of Andreas Krings AutoScaleTextView in order to support resizing according to the TextView height.

 * It works perfectly in all the devices I have tried (Nexus 4, HTC One, HTC Wildfire S, GT-N7102)

 *

 * @author Héctor Berlanga - www.codigojavaoracle.com/android-2/ajustar-textview-android/

 * @version 1.1

 *

 */

/**

 * A custom Text View that lowers the text size when the text is to big for the

 * TextView. Modified version of one found on stackoverflow

 *

 * @author Andreas Krings - www.ankri.de

 * @version 1.0

 *

 */

public class AutoScaleTextView extends TextView {

    private Paint textPaint;

    private float preferredTextSize;

    private float minTextSize;

    public AutoScaleTextView(Context context) {

                this(context, null);

    }

    public AutoScaleTextView(Context context, AttributeSet attrs) {

                super(context, attrs);

                this.textPaint = new Paint();

                this.minTextSize = 2;

                this.preferredTextSize = 200;

    }

    /**

     * Set the minimum text size for this view

     *

     * @param minTextSize

     *            The minimum text size

     */

    public void setMinTextSize(float minTextSize) {

                this.minTextSize = minTextSize;

    }

    /**

     * Resize the text so that it fits

     *

     * @param text

     *            The text. Neither <code>null</code> nor empty.

     * @param textWidth

     *            The width of the TextView. > 0

     */

    private void refitText(String text, int textWidth) {

                this.minTextSize = 2;

                this.preferredTextSize = 200;

                if (textWidth <= 0 || text == null || text.length() == 0)

                        return;

                // the width

                int targetWidth = textWidth - this.getPaddingLeft()

                        - this.getPaddingRight();

                int targetHeight = this.getHeight() - this.getPaddingTop()

                        - this.getPaddingBottom();

                final float threshold = 0.5f; // How close we have to be

                this.textPaint.set(this.getPaint());

                while ((this.preferredTextSize - this.minTextSize) > threshold) {

                        float size = (this.preferredTextSize + this.minTextSize) / 2;

                        this.textPaint.setTextSize(size);

                        int textHeight = getTextHeight(text, this.getPaint(), targetWidth,

                                size);

                        if (this.textPaint.measureText(text) >= targetWidth

                                || textHeight >= targetHeight) {

                        this.preferredTextSize = size; // too big

                        } else {

                        this.minTextSize = size; // too small

                        }

                }

                // Use min size so that we undershoot rather than overshoot

                this.setTextSize(TypedValue.COMPLEX_UNIT_PX, this.minTextSize);

    }

    @Override

    protected void onTextChanged(final CharSequence text, final int start,

            final int before, final int after) {

                this.refitText(text.toString(), this.getWidth());

    }

    @Override

    protected void onSizeChanged(int width, int height, int oldwidth,

            int oldheight) {

                if (width != oldwidth)

                        this.refitText(this.getText().toString(), width);

    }

    // Set the text size of the text paint object and use a static layout to

    // render text off screen before measuring

    private int getTextHeight(CharSequence source, TextPaint originalPaint,

            int width, float textSize) {

                // Update the text paint object

                // modified: make a copy of the original TextPaint object for measuring

                // (apparently the object gets modified while measuring, see also the

                // docs for TextView.getPaint() (which states to access it read-only)

                TextPaint paint = new TextPaint(originalPaint);

                // Update the text paint object

                paint.setTextSize(textSize);

                // Measure using a static layout

                StaticLayout layout = new StaticLayout(source, paint, width,

                        Alignment.ALIGN_CENTER, 1.0f, 0.0f, true);

        return layout.getHeight();

    }

}